Connecting switch



Aug. 31, 1954 E. o. SWANSON CONNECTING SWITCH Filed Sept. 24, 1951 2 Sheets-Sheet l ENTOR.

Aug. 31, 1954 E. o. SWANSON CONNECTING SWITCH 2 Sheets-Sheet 2 Filed Sept. 24, 1951 I JNVENTOR.

, Elmer U. Swanson J WWJ- Patented Aug. 31, 1954 CONNECTING SWITCH Elmer O. Swanson, Chicago, 111., assignor to Motorola, Inc., Chicago, 111., a corporation of Illinois Application September 24, 1951, Serial No. 248,067

The present invention relates to electric switches and more particularly to improvements in high power coaxial cable switches.

Many radio transmitting systems and all television transmitting systems operate in the relatively high frequency portions of the radio frequency spectrum. Radio frequency currents at these high frequencies have such properties that they may be transmitted or piped through coaxial cables or the like. Recent developments in the art have resulted in high power applications of these high frequency currents. Nearly all high frequency transmission systems use coaxial cables at some point in the system to control the direction and application of the high frequency currents and switching devices may be provided to switch the connections between a plurality of the coaxial cables.

When the coaxial cables are conducting high frequency current of relatively high power the construction of coaxial switches for use therewith is complicated by the requirements of adequate insulation. Due to the skin effect property of high power high frequency current, only those insulating materials of very high dielectric strength such as ceramics and the like may be used to insulate the coaxial switching contacts or other elements of the switch. However, such insulating materials have poor mechanical strength and are quite fragile. When used in high power applications, the coaxial switch should be operated by remote control, and it has been found that the switch operating mechanism must be carefully controlled in its movement to prevent damage to the relatively fragile insulation materials of the switch.

It is therefore an object of the present invention to provide an improved form of power operated coaxial switch construction for use with high power high frequency current that is dependable in operation and simple in construction.

Another object of the invention is to provide a form of power operated remote controlled coaxial switch having adequate insulation for operation to switch high power high frequency current, the powered switching operation of the switch being controlled in its application to prevent damage to the switch insulation.

A feature of the invention is the provision of a switch housing containing a plurality of switch contacts in spaced axial alignment, and a reciprocating switch operating arm formed of high dielectric insulating material having a conducting sleeve secured thereto for establishing an electrical connection between selected ones of the switch contacts as the arm is reciprocated in axial alignment with the switch contacts.

Another feature of the invention is the provision of electric power means for reciprocating the switch arm of ceramic insulating material 1 Claim. (Cl. 200-97) 2 together with an associated mechanical dashpot to control the reciprocation of the switch arm and prevent breakage of the arm by sudden power applications.

Further objects, features and the attending advantages of the invention will be apparent upon consideration of the following specification and drawings in which:

Fig. 1 is a side elevational view partly broken away showing the power operated high power high frequency coaxial switch;

Fig. 2 is a detailed perspective view of the reciprocal operating arm of the switch;

Fig. 3 is an end view of the switch as seen in Fig. 1;

Fig. 4 is a longitudinal section on the line 4-4 of Fig. 1 showing the arrangement of coaxial cable switching contacts; and

Fig. 5 is a perspective detail of a coaxial cable switch contact.

The power operated high frequency, high power coaxial switch of this invention is comprised of a metallic switch housing preferably formed from a single rectangular bar of metal hollowed out lengthwise to provide space for the coaxial cable switch contacts and a switch operating arm. The switch operating arm is journalled in bearings on the housing to be reciprocated lengthwise through the space of the housing and establish contact between selected ones of the coaxial cable switch contacts. The coaxial cable switch contacts are located in axial alignment at spaced positions along the switch housing. In order to provide adequate insulation the switch arm is formed from a rod of high dielectric material such as a ceramic material, and is provided with a short sleeve of conducting material secured thereto for selectively establishing contact between the various coaxial cable contacts as the switch rod is reciprocated. Electric solenoid driving means are secured to an outer side of the switch housing and their armatures are connected by a connecting member and pivoted lever to the switch arm for reciprocating the same. A dashpot mechanism is also connected to the connecting member to prevent a sudden application of power to the relatively fragile switch arm which might possibly break the arm.

Referring to the drawings, the switch block or housing is shown at ID. The housing I0 is preferably constructed from a single rectangular bar of metal and is bored lengthwise to provide the hollowed out portion ll. Metallic end plates 12 and 13 are fastened to the switch block to form a closed housing. The end plates [2 and t3 are provided with bearing holes M and :5 respectively, to receive a reciprocating switch operating arm generally shown at l 6.

The switch operating arm H5 is shown in detail in Figs. 2 and 4 of the drawing and includes a cylindrical rod ll of high dielectric ceramic material or -the like. One end of the ceramic rod I1 is cementedto a metallic collar I8 which is pivotally connected at l9 to a metallic bearing cylinder 28. The bearing cylinder 29 is journaled in the hole 15 of the end plate I3 and is pivotally connected at 2i to an operating lever 22. The other end of the ceramic rod H is cemented to the metal collar 23 pivotally connected at 24 to the metallic bearing cylinder 25 adapted to be journaled in the hole Id of the end plate 12.

Mounted at spaced lengthwise positions in axial alignment within the hollowed space H of the switch block Ill are a plurality of coaxial cable switch contacts 30, 3|, and 32 (Fig. 4).

Each of the coaxial cable switch contacts are connected to the inner conductor of a coaxial cable whose outer conductor is connectedto the metal switch housing It through a metal plate such as the metallic plate 33 shown in detail in Fig. 5 of the drawings. Each of the coaxial cable switch contacts, such as the switch contact 33, are provided with a plurality of spring contact fingers such as those shown at 34 and 35 positioned on opposite sides of the switch operating arm l6.

The switch operating arm It includes a sleeve 36 of conducting material supported on the ceramic rod H. The sleeve has an annular opeing for receiving the ceramic rod and a square cross section to provide flat surfaces engaged by the fingers of the coaxial cable contacts. The flat surfaces are preferably silver plated and are of a length to form a bridging connection between either coaxial cable contacts and 3 l, or coaxial cable contacts 3! and 32 as shown in Fig. l of the drawings, depending upon the position of the reciprocable switch arm. The contact fingers 34 and 35 of the coaxial cable switch contact 39 are adapted to provide a wiping contact with opposite fiat surfaces of the contact sleeve 35 and may also be silver plated to minimize the resistance losses of the high frequency currents to b switched. The contact sleeve 36 may be secured to the ceramic rod ll by means of cement.

It will be apparent that the reciprocal switch operating arm it is relatively fragile, since it includes the ceramic rod ll with the contact sleeve 35 cemented to the center thereof and the metal collars it and 23 cemented to the ends. The power mechanism for reciprocating the switch arm it must therefore be controlled in its application to prevent breakage of the switch arm. To this end electric solenoids 6 and ii are secured to one side of the switch housing l and each solenoid is provided with an armature t2 and The armatures l2 and 53 are joined together by a U-shaped connecting bar or arm 44. Also pivotally connected at 55 to the connecting arm M is the rod 45 and piston 37! of an air dashpot including the cylinder at secured to an extended portion of the end plate l2.

A pair of pedestal plates 58 and are secured to the switch block it and one end of the lever arm 22 is pivoted at 53 between the pedestal plates. The connecting bar i l is pivotally secured at 5 to the lever 22 intermediate its length. The lever arm 22 is pivotally connected at ill to the bearing cylinder 2b of the switch operating arm It.

To operate the switch a selected one of the solenoid coils Gil or iii is energized to move the connecting bar id, lever arm 22, and switch operating arm H5 in a particular direction. As

will beapparent from Figs. 1 and 4, energization of solenoid 40 causes movement of the arm it to the left to connect contacts 36 and 31. Similarly, energization of solenoid 41 will cause movement of the arm Hi to the right-to connect contacts 31 and 32. A coaxial cable connected to contact 3! may therefore be selectively connected to cables connected to contacts 30 or 32. The air operated dashpot comprised of the piston 4'1 and cylinder 48 will prevent the sudden movement which would normally take place when either the solenoid coil ll] or M is energized.

The coaxial cable switch as disclosed has been found to be highly satisfactory in actual use. This i to be contrasted with switches which did not include the vdashpot and in which the conducting sleeve on the ceramic rod broke loose therefrom as the switch was operated by the solenoids. When the sleeve was secured firmly to the ceramic rod as by a pin, the force of movement caused the ceramic rod to break. The use of the dashpot to control the movement of the arm has obviated these difiiculties and provided a commercially successful article.

While the coaxial switch of the present invention has been described particularly in reference to an application for switching the connections between three coaxial cable switch contacts, it will be obvious that the principles of the invention may be applied equally as well to the switch construction for various numbers of coaxial cable contacts, and having various numbers of conducting sleeves on the insulated switch operating arm. Similarly, the position and arrangement of the conducting sleeve on the insulated arm may be modified to suit particular applications. Such changes are within the intended scope and spirit of the invention as defined by the appended claim.

I claim:

In a coaxial switch assembly having an elongated conductive housing forming a longitudinal cavity, a plurality of coaxial cable connectors secured in spaced relation along said housing and each having an outer conductor electrically connected to said housing and an inner conductor extending into the cavity within said housing, conductive end plates enclosing said cavity and having aligned openings therein, and a switch arm journaled in said openings in said end plates including a fragile rod of high dielectric material with a conductive sleeve secured thereto and extending over a portion of the length thereof, said switch arm being capable of reciprocal motion'in said cavity for selective engagement of said conductive sleeve with the respective inner conductors of said coaxial cable connectors, the combination of at least one solenoid, a bar actuated by said solenoid for reciprocal motion along an axis parallel to and spaced from the axis of reciprocal motion of the aforesaid switch arm, linkage means for coupling said bar to said switch arm to impart reciprocal motion thereto, and an air operated dash pot mounted coaxially with the axis of reciprocal motion of said bar and having a piston coupled to said bar to prevent sudden movement of said bar by said solenoid.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,101,494 Kirchhoff June 23, 1914 2,235,010 Chaffee Mar. 13, 1941 2,550,921 Green May 1, 1951 

